1. Field of the Invention
This invention relates to a television camera and particularly to a television camera for producing a video signal suited for still picture reproduction.
2. Description of the Prior Art
Electronic still picture is reproduced by a display having a scan converter for forming a video signal indicative of still image from an NTSC (interlace type) video signal by storing a video signal of two fields, i.e., a frame; then repeatedly reading the stored video signal; and sending the video signal to a non-interlace TV monitor. An electronic still picture television system is shown in FIG. 17. In FIG. 17, a video image is recorded onto a video tape in the VTR 2 through a television camera 1 preferably having an electronic shutter. The television camera 1 may be built into the VTR 2 as a single unit VTR build-in type camera. The VTR 2 reproduces still image in a field still mode or a frame still mode. Reproduced still image is displayed on a display 3 or recorded as an electronic photograph, i.e., a hard copy of the still image by a printer 4. The display 3 comprises a scan converter 3a and a non-interlace type television receiver 3b. For convenient displaying, a general television receiver is usable.
In reproduction of an electronic still picture from the above prior art system, there is a drawback that the reproduced still image has lower vertical resolution than a photograph obtained by a conventional film with a photochemical process. One of the reasons is as follows:
In the conventional type still picture reproduction system of FIG. 17, which reproduces still picture from interlace type video signal of only one field of a frame (two fields) is recorded, so that the vertical resolution of the recorded still image is one half the vertical resolution of the normally displayed image of two complete fields. On the other hand, if still picture was produced from video signal of two fields which make up a frame of interlace scanning there would be a drawback that reproduced picture may exhibit a double line image as shown in FIG. 18 when an object moves in a short period of time between consecutive fields, though vertical resolution in this case would be the same as that of the normally displayed image of two complete fields.